Kia Optima vs Mercedes-Benz S-Class

What's the difference?

If you travel long distances, want a good amount of space and don’t want to pay big bucks for a new car, then yeah, maybe there is a reason sedans like this will hang around for a while longer.

Sure, the appeal of sedans mightn’t be as strong as it once was, but models like the Kia Optima prove they still have a reason to exist.

Mercedes-Benz set out to restore the S-Class' place amongst the greatest sedans in the world.

In the heavily-optioned, near-$250K-plus S450 as well as the extended S450L at $300K as tested (the sweet spot of the range for now), we reckon the Germans have succeeded, pushing safety, comfort and technology boundaries, in a package that is true to the heritage of the series.

Tax-fuelled sky-high prices will certainly keep the S-Class niche in Australia, but the car is more than good enough to dominate its tiny corner of the upper-large luxury car sphere.

The best new car in the world? We reckon it's highly likely. Mission accomplished, Mercedes.

Cosmetic changes for the facelifted 2018 Kia Optima include new headlights and tail-lights with revised LED signatures (but still halogen lamps in the base model), and there are newly sculpted bumpers and new wheel designs across the two-model range. 

We had the base model Si, which doesn’t look as good as the GT model, because it has smaller wheels, the sporty body kit and misses out on the LED headlights, but the LED daytime running lights are still present.

The GT has a more aggressive look, and the side skirts, front spoiler and rear diffuser fit it better - there are dual exhausts, but not sporty quad exhaust tips.

In fact, this model is a bit like the old-man version of the Optima. No offence intended to old men, of course. The GT is just heaps sportier, and I reckon it’s considerably more attractive as a result. 

Still, the inherent sleek styling of the Optima remains - the chrome highlighting along the window line is a bit too sheeny for me, but the angles and stance of this model are quite gracious. I really dig the fact the top of the windscreen mirrors the ‘Tiger Nose’ grille shape.

I'm no exterior designer, but I liked the existing Optima more - it just looked a bit neater, even though it had a decent amount of bling with its Mercedes-like diamond-pattern grille, as opposed to the cheese grater look seen here.

There’s not quite as much bling inside the cabin of the Si, either, but it is still a well-designed space - just not as special as the premium package offering of the GT (which gets leather trim - not nappa leather, but still a quality cowhide finish, and more). Check out our interior photos to see if you agree - but size and interior dimensions of the Optima are hard to argue against.

Most Mercedes models have followed the Russian Doll-style cookie-cutter styling theme, and the heavy family look continues with the W223.

Still, the flush door handles do add a touch of Tesla-esque modernity, while the elegant silhouette and clean lines are in keeping with the luxury aspirations. Larger in every dimension compared to the old W222, the S450 is some 71mm-longer in wheelbase (3106mm) than before while the LWB's has stretched out by 51mm (3216mm), benefiting proportions as well as interior packaging.

AMG-branded wheels look sporty but – in the S450 at least – they're perhaps a tad too gangster. A set of flush alloys would give it a more-modern and techier appearance, in our opinion.

Overall, however, the S-Class ‘7' possesses the prerequisite richness of design. It isn't as bold and mould-breaking as models like the W116 were back in their day, but the styling is still a success.

By the way, the latest S-Class is the first Mercedes to employ the MRA2 longitudinal platform, which is rich in lightweight steels (50 per cent aluminium), is correspondingly stronger than before but also 60kg lighter.

With a drag co-efficiency rating as low as 0.22Cd on some overseas grades, the W223 is one of the most aerodynamic production vehicles in history.

I really like the way Kia designs its cabins. Sure, there’s a lot of black in here, but there’s also a lot of thought put into the usability of the space.  

The high-mounted 7.0-inch infotainment and multimedia touch screen in the Si is simple to use, and for 2018 the Optima range gets Apple CarPlay and Android Auto - you couldn’t get that in the Optima up to this point. 

Also included are a reversing camera, USB input, Bluetooth phone and audio streaming and six speakers. The Si model misses out on sat nav - you’ll have to use the maps app on your phone. No DVD player either.

Storage is well thought out in here, with big bottle holders in the doors, a good sized pair of cup holders up front, and a nice little storage bin for your phone, wallet, keys and so on.

There’s a driver info screen with a digital speedo, and even on this base model you get a dual-zone climate control air conditioner. The updated Optima gets a new steering wheel, too.

Now, what about the back seat?

It may be considered a ‘mid-sized’ sedan, but there’s limo-like space. With the driver’s seat in my position (I’m about six feet tall) there was still heaps of rear legroom in the rear seat, with ample knee room, good foot room and decent shoulder space, too - three of me could slot across the back bench comfortably, which means kids will fit easily, too. There are three top-tether points and two ISOFIX points as well.

Kids and adults alike will be happy with the rear air vents back here, and there’s a flip down armrest with cupholders, too. Again, big bottle holders appear in the doors, and there are map pockets in the back seats.

What about boot space? With so many people choosing SUVs over sedans because they’re theoretically more practical, the Optima offers good food for thought - it has enough luggage capacity for a bunch of suitcases (510 litres VDA in size) and there’s a full-size alloy spare under the boot floor. If you need more, you could always invest in a roof rack setup?

For the beginning of our day with the S-Class, we were chauffeured from home to a mansion in Kew, a blue-chip Melbourne suburb. Our heavily-optioned S450L featured most of the aforementioned extras – including the Business Class Package and Rear Entertainment Package – and the experience was predictably, sumptuously memorable.

Reclining individual rear seats with easy-reach tablets, armrests offering access to all multimedia and available climatised and massaging cushions and backrests... we're no longer in our normal ride, Toto.

Yet, all these trinkets and gizmos are mere add-ons, that can turn a stretched Caprice into a flash hen's night carriage if enough money and glitz is thrown at it.

No, the new S-Class must impress in an altogether less tangible and more philosophical manner, involving all the senses, and not just what we see, hear and touch. It must appeal beyond the superficial. Otherwise, it is not a large Mercedes-Benz luxury sedan in the classic manner.

This is a Herculean task for the Stuttgart designers and engineers. By and large, though, the Three-Pointed Star has succeeded in achieving something special.

In its perception of peerless quality and engineering, the W223 is striving to move forward and look back simultaneously to the glory days of the seminal W126 (1980-1991). This is through meshing traditional virtues like solidity and quality materials while dazzling its passengers with technology that is still friendly enough to want to enhance your experience.

You can sink into the soft lounge seats, watch the world pass by silently outside and never be aware of the road underneath or the engine ahead. Double glazing, exquisite and aromatic fabrics and materials and lush tactile surfaces work their magic inside the car, while an airtight and aero body, solid platform, air suspension and a muted yet muscular powertrain all do their thing underneath. The atmosphere is special and rarefied. That's what an S-Class needs to be and that's what is happening in our $299,000 (as tested) S450L.

The same more-or-less applies up front, as the same trim, leather, wood and technology surrounds the driver and passenger. The spectre of the car that is surely The Car of the Last Decade – Tesla's Model S – is evident in the portrait touchscreen and sparse, almost wallflower dashboard design and layout. No big imposing architectures here.

Yet, while the American upstart actually takes stuff away, the S-Class packs the cabin with subtle features that – like when the planes stopped flying last year and the birdsong subsequently returned – only become obvious once the cabin's design simplicity clears all the white noise for you to be in a better frame of mind to enjoy them.   

Take the haptic interface, for example, as it is perhaps the best we've experienced; the sense of well-being garnered from the cumulative effects of profound seat comfort (the massaging function was never switched off), cocooning micro climate environmental control, orchestral levels of audio entertainment and the theatre of light and vision performed by the two available screens; it is an automotive experience like no other. And the eye-tracking 3D-effect navigation set within the electronic instrumentation. No need for cinematic glasses to get the effect. The driving position itself, by the way, is also first class.

Room to stretch and grow for sure, and in every direction. But room for improvement? You betcha.

Your tester had a headache after a little while staring at that woozy 3D map. The central vents – four at the front, two in the rear – look and feel cheap, leaving us mentally redesigning them; they are frightfully out of place here; the carryover column-stalk auto lever should have been binned in 2005. And, even though the digital instruments have a number of options, none are elegant enough for the S-Class. That's an especially subjective criticism, clearly, but one that – in the context of classic Mercedes luxury sedan contenders – is justified given how timeless the Bruno Sacco era of Daimler design was. Look him up, kids.

Still, after a couple of hours behind the wheel, with our senses reset to calm, it is obvious that the S-Class cabin is a unique and wonderful place – as it should be at a cool quarter-of-a-million dollars.

Job done.

PS At 550 litres (20L more than before), the boot is massive and luxurious enough to sleep in.

Right now, only two S-Class models are available – the S450 from $240,700 plus on-road costs and the 110mm extended-wheelbase S450L (LWB) for another $24,900 on top. Most buyers overwhelmingly opt for the latter.

Despite what the numbers may suggest, both are powered by a 3.0-litre in-line six-cylinder turbo petrol engine, delivering 270kW of power and 500Nm of torque to all four wheels via a nine-speed torque-converter automatic. Greater choices are coming later, including an all-electric version known as the EQS.

Almost every conceivable safety item is standard on the S-Class, including world-first rear-seat airbags located behind the front seats in the LWB model, taking the surround-airbag count to 10.

You'll also find route-based Speed Adaptation (adhering to the posted speed limits), Evasive Steering Assist (a sophisticated form of crash mitigation), adaptive cruise control with active stop/go, Active Lane Change Assist that automatically moves the car into the lane you indicate to), Mercedes' PreSafe crash-preparation tech that primes all the safety systems for impact, electronic stability program that encapsulates all the active driver-assist tech, Active Emergency Stop Assist, Autonomous Emergency Braking front and rear (including for cyclists and pedestrians), Traffic Sign Assist, Parking Package with Active Parking Assist and 360-degree camera and tyre pressure monitors.

On the equipment front there is the latest iteration of Mercedes' MBUX multimedia system with (another) world-first 3D display, complementing an OLED central display, powered closing doors, leather upholstery, air suspension, leather upholstery, velour floor mats, a multi-beam LED headlight system with adaptive high beams, heated and folding exterior mirrors, heat and noise-insulating acoustic glass for front side windows, dark privacy glass for rear windows, sunroof, roller sunblinds for rear windows, metallic paint and 20-inch AMG alloy wheels on runflat tyres.

Want cutting-edge multimedia? There's MBUX II's augmented reality for navigation and fingerprint scanner, as well as a more natural-speech Mercedes-Me Connect voice activation with global search.

Plus, predictive navigation with live traffic, parked vehicle locator, vehicle tracking, emergency call, maintenance management and tele-diagnostics, digital radio, Burmester 3D surround-sound system with 15 speakers and 710W amplifier, remote door locking/unlocking, geofencing, speed-fencing, valet parking, head-up display, Smart Phone integration with Apple CarPlay/Android Auto, wireless charging, ambient lighting, two-zone climate control, poplar wood trim, electric adjustment for front seats, steering column with memory function, climatised front seats, keyless entry/go with flush-fitting door handles offering hands-free access (including for the electric boot),

Besides the ‘forward facing' airbag for the rear-seat occupants, the S450L also scores electrically adjustable rear seats with memory and automatic rear climate control.

Key options – and the list is massive – include an $8700 Rear Entertainment Package, that brings rear-multimedia access, rear tablets with wireless headsets and rear-seat wireless smart phone charging, an AMG Line pack with a body kit, different alloys and larger front brakes ($6500), Business Class Package that includes aircraft-style reclining rear seating and tray tables ($14,500), Nappa leather ($5000), augmented-reality HUD ($2900), 21-inch wheels ($2000) and four-wheel steering ($2700). There's also a $14,500 Energising Package with contoured seating, heated-everything and massaging seats.

Please keep in mind our test cars featured many such extras. Tick all the boxes and you can add nearly $100,000 to the price of your S-Class.

So, is the S450 good value? Given some of the breakthrough safety and luxury features it offers, it is unique. Too bad the Federal Government's Luxury Car Tax makes them so much more expensive than they need to be.

The Si model is powered by a 2.4-litre four-cylinder petrol engine, which has seen no changes to its specifications for this mid-life update.

Engine specs remain at 138kW of power at 6000rpm, while torque is rated at 241Nm at 4000rpm. It makes use of a six-speed automatic transmission only - there’s no manual transmission here, but you do get paddle shifters - and it's front wheel drive (the Optima isn't available with AWD, or as a 4x4, or in rear wheel drive - the latter is left to its bigger brother, the Stinger).

The GT gets a zestier drivetrain with more horsepower - it has a 2.0-litre turbo four-cylinder engine with 180kW/350Nm, which is much more desirable, but also louder than the Si’s 2.4. It also has a six-speed auto transmission, and is FWD. If you're into ratings and statistics, that 2.0-litre with a turbocharger is one of the perkier offerings for its engine size in the class.

There is no hybrid model available, despite a plug in hybrid petrol version (allowing you to run in EV mode) being sold in European markets. No diesel here, either, while other markets get a 1.7-litre turbo diesel. No LPG model here, or anywhere else, for that matter.

Towing capacity for Optima models is 750kg unbraked and 1700kg braked for the 2.4-litre, and 700kg/1400kg for the 2.0-litre turbo. Tow bar down-weight is capped at 80kg.

If you're concerned about engine problems, suspension problems, clutch and transmission issues, be sure to check out our Kia Optima problems page.

Where are the V8s?

Right now, the only W223 you can buy is powered by an all-new 2999cc 3.0-litre in-line direct-injection six-cylinder turbo petrol engine dubbed the M256, complete with double overhead cams, an electric compressor intercooler and assistance from a 48-volt mild hybrid system and integrated starter-generator, adding 16kW and 250Nm to the 270kW of power at 6100rpm and 500Nm of torque from 1600-4500rpm.

The 9G-Tronic torque-converter automatic transmission and 4Matic all-wheel drive system combination is a first for the S-Class in Australia.

Top speed is limited to 250km/h, while the 0-100km/h sprint-time takes just 5.1 seconds in both models. Impressive for a two-tonne-plus luxury limo.

Kia claims a very realistic fuel economy rating of 8.3 litres per 100 kilometres for the Si model, and we saw damn close to that consumption during our week of testing. On the highway it will sit at around 6.5L/100km, ensuring good mileage, while city driving will push usage above 12.0L/100km. Our overall average was 8.5L/100km, which is good. Use the eco mode, and you'll get a little better use.

The turbocharged GT model uses a little more, according to Kia’s 8.5L/100km combined average claim, but we guarantee you’ll actually use more than that because it’s more eager to please.

Fuel tank capacity is 70 litres - plenty of size for long distance drives.

With the aid of the mild-hybrid system, the S450 returned a combined average of an impressive 8.2 litres per 100km, which translates to 187 grams of carbon dioxide emissions per kilometre. 95 RON premium unleaded (or higher) is recommended. In the urban run it consumes 11.3L/100km (11.5 for S450L), and just 6.4L/100km (6.5 for S450L) in the extra-urban result.

At 76 litres, the fuel tank will allow a combined average range of about 927km between refills.

The Optima has some really good elements to the way it drives, but sadly  some less impressive bits as well.

Let’s start with the not-so-great stuff - the 2.4-litre engine in this Si model just isn’t as enjoyable as the turbo unit, and the fact that Kia still doesn’t offer a hybrid version here, despite doing so elsewhere, is a bit of a downer.

The drivetrain isn’t terrible - the six-speed auto is smart enough, and there’s usable power if you boot it. The two more sedate drive modes, 'Eco' and 'Comfort', mean the transmission will aim to save fuel and limit throttle response, with a bit more of a lazy feel to the drive experience. But in 'Sport' mode it is definitely more rewarding in terms of acceleration and performance, offering a bit more pep and urgency (we didn't do a 0-100 km/h speed test, but take our word for it); it undoubtedly at the cost of fuel consumption.

It’s just a bit of a shame Kia doesn’t offer the turbo in this spec, too. Fuel use for the Si model is better than the turbo, however, so it could be ideal for buyers who are more worried about the bottom line than design and a sportier drive.

The thing I like most about the Optima is its road manners - the steering and suspension have been tuned for local conditions, just like all Kia products, and it shows. 

The electric power steering is really well sorted, making for easy parking moves and good assuredness at higher speeds. And the turning circle is decent, too - 10.9m (so, the turning radius is 5.45m). 

Plus the ride comfort is really good. On the highway it coasts along with very little fuss, and around town it deals with lumps and bumps impressively. Sharp edges can upset things a tad, and mid-corner bumps can make it jitterbug a little bit, but not to a degree that would rule it out of contention if you want a mid-sized sedan.

It’s pretty quiet on the open road, too, and the adaptive cruise control makes long-distance driving a simple task. The GT does suffer a little bit more road noise, though.

In former times, as the Germans say, a ‘450' on the boot indicated V8 power. In the W116 S-Class era it was one of the world's most evocative badges when ‘SEL' was also attached.

As mentioned earlier, though, it's the M256 3.0-litre turbo-petrol with a 48-volt ‘mild hybrid' electrical system that's doing the driving, to all four wheels. The real V8 W223 will probably surface later this year or in early 2022 with the S580L flagship. Bring it on.

This is not to say that S450 isn't good enough. With that electrified assistance, the blown straight six is smooth and swift off the line and rapid as the auto seamlessly steps up through all nine gears. Because it's so hushed and refined, it doesn't feel 5.1s to 100 clicks quick, but watching the speedo says otherwise – acceleration is assertive and strong right up way past the legal speed limit.

All that's missing is the burbling soundtrack of a classic Benz bent-eight. Oh well. Outstanding economy is a price we're literally willing to pay in lieu.

Even more impressive is the S450's ability to hustle along mountain roads like an overgrown sports sedan.

Now, for Australia, all S-Classes are fitted standard with an adaptive ‘Airmatic' air-suspension set-up, including air springs and self-levelling tech. In Comfort up to 60km/h, the ride height can be raised by 30mm, or lowered by 10mm under the standard 130mm baseline in Sport at any velocity, while in Sport+ it falls another 17mm.

With that in mind, yes, the standard air suspension performs a magnificent job smothering out most surface imperfections around town. Yet its real other party trick is to tighten up the chassis when corners get interesting and Sport mode is selected. Aided by progressively weighted and reassuringly responsive steering, the Mercedes tips into turns with precision and poise, slicing through with virtually no discernible body lean or understeer.

Now, we're not talking a leisurely drive on rural highways here, but Healesville's famous Chum Creek Road, where even a Porsche Cayman would feel like it's had a strenuous dynamic workout. The S-Class can be hurried along with confidence and finesse, displaying outstanding handling and roadholding for a 5.2-metre long limo. And the fact that the ride quality only suffers marginally when the red horns are out is all the more remarkable.

Back in the cut-and-thrust of inner-city peak-hour traffic, the Benz in Comfort mode continued to reveal its driver-orientated yet passenger-focused twin-personalities, zipping in and out of gaps while remaining comfy and composed inside.

Only when parking in tight spots are you truly aware that the W223 is longer than a Mazda CX-9. The optional four-wheel-steering system is claimed to slash the turning circle to A-Class hatchback levels. 10.9 metres is the claim.

The 2021 S-Class never ceases to amaze and delight.

The W223 S-Class has not been crash-tested yet by ANCAP or European affiliate EuroNCAP, so does not have a star rating. However, Mercedes-Benz claims it has striven to create one of the safety vehicles on the planet. Who are we to argue?

Almost every conceivable safety item is standard on the S-Class, including world-first rear-seat airbags located behind the front seats in the LWB model, taking the surround-airbag count to 10.

You'll also find route-based Speed Adaptation (adhering to the posted speed limits), Evasive Steering Assist (a sophisticated form of crash mitigation), adaptive cruise control with active stop/go, Active Lane Change Assist that automatically moves the car into the lane you indicate to), Mercedes' PreSafe crash-preparation tech that primes all the safety systems for impact, electronic stability program that encapsulates all the active driver-assist tech, Active Emergency Stop Assist, Autonomous Emergency Braking front and rear (including for cyclists and pedestrians, at speeds from 7km/h to over 200km/h), Traffic Sign Assist, Parking Package with Active Parking Assist and 360-degree camera and tyre pressure monitors.

The Active Lane Keeping Assist works in a speed range of between 60km/h and 250km/h while Active Steer Assist helps the driver follow the lane at speeds of up to 210km/h.

Kia remains a shining light in terms of its new-car-ownership promise, with a very strong seven-year/unlimited kilometre warranty. It makes a lot of sense if you plan to hang onto the car for a while. There's no extended warranty available, which is understandable.

That plan also includes a roadside-assist plan for the same seven-year period, provided you maintain your car with Kia Australia. So, given you get one year to start with, then you get an extra year of cover every time you go back to Kia to get your car serviced, you could end up with eight years of coverage. Nice!

Servicing is due every 12 months or 15,000km, with the first seven years covered by a capped-price-service cost / maintenance cost plan. The costs are: service one - $289; two - $466; three - $360; four - $559; five - $325; six - $599; seven - $345. That makes a total cost of $2943, which is competitive for its class. Keep your owners manual or logbook up to date, and your resale value should hold up better.

If you have concerns about common problems, issues, reliability ratings and durability, you should check out our Kia Optima problems page.

Unlike many luxury brands that persist with a sub-par three-year warranty, Mercedes-Benz offers a five-year/unlimited kilometre warranty.

Intervals are every year or 25,000km, with a capped price service plan starting at $800 for the first year, $1200 for the second year and $1400 for the third year, totalling $3400. Alternatively, there is a Service Plan starting at $2700 for the first three years (saving $700 from the normal capped-price service plan), $3600 for four years and $5400 for five years.